In recent years, with the popularization of passenger vehicles equipped with diesel engines, in order to prevent misfueling (use of the wrong fuel type) between diesel engine vehicles and gasoline engine vehicles, for example, in Europe, light oil dispensing nozzles have a larger diameter than gasoline dispensing nozzles, so that the light oil dispensing nozzle cannot be inserted into the filler opening of a gasoline engine vehicle. On the other hand, a nozzle inhibitor may be provided in the filler opening of a diesel engine vehicle, that with the smaller diameter gasoline dispensing nozzle, disables an opening operation of a predetermined nozzle insertion restricting member to prevent the insertion thereof, and only with a larger diameter gasoline dispensing nozzle, enables the opening operation of the nozzle insertion restricting member, to permit the insertion thereof (refer for example to Patent Document 1).
[Patent Document 1] Specification of U.S. Pat. Publication No. 7,077,178